I have been trying to digest much of Porter's understanding of Greek Verbal
Aspect. What seems to stand out is the unnatural way in which it must have
been spoken, if his non-temporal verbal system is correct.

It seems to me that typical conversations would have to be loaded with
deictic indicators for even the most casual of conversations.

And I can not even imagine a parent trying to teach a child how to begin to
talk in simple concepts. Did parents simply teach their children to speak in
the Aorist (his "default" form)?

His system seems counter-intuitive to how we learn to talk. And it seems to
me that a particular language is FIRST spoken, and THEN written.